共查询到20条相似文献,搜索用时 46 毫秒
1.
Mahmood Tajbakhsh Moosa Ghaemi Siavosh Sarabi Mitra Ghassemzadeh Majid M. Heravi 《Monatshefte für Chemie / Chemical Monthly》2000,131(11):1213-1216
Summary. N-Methyl piperidinium chlorochromate adsorbed on alumina oxidizes a wide variety of benzylic alcohols to the corresponding
carbonyl compounds.
Received May 18, 2000. Accepted (revised) July 4, 2000 相似文献
2.
György Göndös György Dombi James C. Orr 《Monatshefte für Chemie / Chemical Monthly》2000,131(10):1055-1059
Summary. The synthesis of a new chiral boroxazolidine was achieved which was used to control the stereochemistry of the borane reduction
of the 20-keto group of steroids. The otherwise hardly accessible 20α-(20S)-alcohol can thus be prepared in a yield of 91%.
Received April 10, 2000. Accepted (revised) May 2, 2000 相似文献
3.
Rainer Strommer Wolfgang Strauss Helmut Emmert Reinhard Sailer Rudolf Steiner Eva Reisinger Ernst Haslinger Hans W. Schramm 《Monatshefte für Chemie / Chemical Monthly》2001,132(3):387-392
Summary. Selenium dioxide oxidation allows the selective introduction of a hydroxyl group at position 6 of the steroid skeleton of
the antihormone (11β, 17β)-11-(4-dimethylamino-phenyl)-17-hydroxyl-17-(1-propynyl)-estra-4,9-dien-3-one (mifepristone, RU
486) and leads in a one-step procedure to two diastereomeric oxidation products. Their structure (6α- and 6β-hydroxy-mifepristone)
was determined by NMR spectroscopy. The antiprogestinic activity of the oxidation products is comparable to that of mifepristone.
Received August 25, 2000. Accepted (revised) October 24, 2000 相似文献
4.
Babasaheb P. Bandgar Vaibhav S. Sadavarte Lav S. Uppalla Rahul Govande 《Monatshefte für Chemie / Chemical Monthly》2001,132(3):403-406
Summary. A simple and versatile method for the synthesis of oximes, semicarbazones, and tosylhydrazones of aldehydes in the presence
of ketones without catalyst and solvent is presented.
Received June 28, 2000. Accepted (revised) August 25, 2000 相似文献
5.
Summary. Upon irradiation of 3,4-di-O-benzyl-hypericin and proton sponge (bis-1,8-N,N-dimethylamino-naphthalene) in benzene solution, a stable radical ion pair formed which exhibited an intense absorption
band around 800 nm. This was advanced by UV/Vis, NMR, and ESR spectroscopy. In presence of oxygen, irradiation of this photoproduct
led to an activated oxygen species which then attacked the proton sponge.
Received July 17, 2000. Accepted July 20, 2000 相似文献
6.
Summary. Reaction of solid SiO with CuI, AgI, AgCl, or AgF results in the formation of the silicon tetrahalides SiX
4 and elemental silver or copper. The crystal structure of SiI4 was re-determined (Si-I 2.427(2) and 2.416(4) ?).
Received March 2, 2000. Accepted March 10, 2000 相似文献
7.
Babasaheb P. Bandgar Suhas P. Kasture 《Monatshefte für Chemie / Chemical Monthly》2000,131(8):913-915
Summary. The Friedel-Crafts arylmethylation of aromatics with benzyl halides or bis-(bromomethyl)-benzene in the presence of Envirocat EPZ10? affords selectively para-arylmethylated products in good yields. Isolation of pure products involving an eco-friendly procedure and recyclability
of the catalyst are important features of this method.
Received January 17, 2000. Accepted (revised) March 2, 2000 相似文献
8.
Summary. The reaction of 1,5-diphenylpentanetrione, 4-chlorobenzaldehyde, and acetone in the presence of methylamine resulted in 2,6-dibenzoyl-5-(4-chlorphenyl)-3-methyl-cyclohex-2-en-1-one,
which was formed by a sequence of a Knoevenagel reaction, an aldol condensation, and a Michael addition in a one-pot reaction.
Received August 16, 2000. Accepted September 8, 2000 相似文献
9.
Gülcemal Yıldız Haluk Akkuş Ahmet Gül 《Monatshefte für Chemie / Chemical Monthly》2001,132(6):659-667
Summary. Some porphyrazines with dimethylamino- or trimethylammoniumethylsulfanyl substituents were studied in dichloromethane or
dimethylsulfoxide solution by cyclic voltammetric methods. The cyclic voltammogram of metal free octakis-(dimethyl-aminoethylsulfanyl)-porphyrazine is characterized by three one-electron reduction waves which show quasi-reversible behaviour at all sweep rates observed; the same holds for its cobalt(II) derivative. The quaternized octacationic
derivative, however, exhibits four one-electron reduction waves which are reversible at all sweep rates. The reaction mechanisms
and diffusion coefficients were investigated.
Received October 17, 2000. Accepted (revised) December 11, 2000 相似文献
10.
Konstantinos Kordatos Tatiana Da Ros Maurizio Prato Chuping Luo Dirk Guldi 《Monatshefte für Chemie / Chemical Monthly》2001,132(1):63-69
Summary. Fullerene derivatives exhibit absorption throughout the UV/Vis region up to 750 nm. This feature is important for easy excitation.
Once excited, fullerenes may become both electron and energy acceptors. The distinction between these two pathways depends
strongly on the partner involved (donor) and on the conditions employed (solvent, etc.).
Received June 23, 2000. Accepted July 7, 2000 相似文献
11.
Kenji Yamagata Fumi Okabe Motoyoshi Yamazaki 《Monatshefte für Chemie / Chemical Monthly》2001,132(6):721-729
Summary. The reaction of 4-amino-2,5-dihydro-2- and -5-methyl-3-thiophenecarbonitriles with α-diazocarbonyl compounds in the presence
of rhodium(II) acetate gave regioselectively 4-cyano-2H-thiopyrans (C2-S insertion) in moderate to good yields; 5-cyano-2H-thiopyrans (C5-S insertion) were not isolated. The starting compounds were synthesized by reaction of tetrahydro-2- and -5-methyl-4-oxo-3-thiophenecarbonitriles
with morpholine, piperidine, and pyrrolidine in the presence of formic acid in ethanol.
Received November 13, 2000. Accepted December 12, 2000 相似文献
12.
Weal H. Hegazy 《Monatshefte für Chemie / Chemical Monthly》2001,132(5):639-650
Summary. New β-diketone phenylhydrazones prepared by condensation of substituted 3-arylidene-2,4-pentanediones with phenylhydrazine,
have been characterized by their elemental analyses, IR, 1H NMR, and mass spectra. Some complexes of these Schiff bases with Co(II), Ni(II), and Cu(II) ions have been synthesized; in addition to the above methods, their structures were
studied by magnetic susceptibility and thermogravimetry measurements.
Received January 26, 2000. Accepted (revised) April 14, 2000 相似文献
13.
Visible Photoluminescence in Polysilanes 总被引:1,自引:0,他引:1
Stanislav Nešpůrek František Schauer Andrey Kadashchuk 《Monatshefte für Chemie / Chemical Monthly》2001,132(1):159-168
Summary. The photoluminescence spectrum of poly-(methyl-(phenyl)-silanediyl) shows a strong narrow peak in the UV region which is
of excitonic nature and related to σ*-σ transitions. The broad emission peak in the visible region is related to polymer branching, charge transfer transitions,
and defect electronic states (backbone scission). Chemical substitution of the Si backbone with π-conjugated side groups allows
to generate photoluminescence also in the visible region.
Received June 23, 2000. Accepted (revised) August 7, 2000 相似文献
14.
Issa Yavari Norollah Hazeri Malek T. Maghsoodlou Nader Zabarjad-Shiraz 《Monatshefte für Chemie / Chemical Monthly》2001,132(6):683-687
Summary. The reactive 1:1 intermediate produced in the reaction between 2,6-dimethylphenyl isocyanide and dimethyl acetylenedicarboxylate
was trapped by N,N′ -dimethylbarbituric acid to yield the isomeric products dimethyl 7-(2,6-dimethylphenylamino)-1,3-dimethyl-2,4-dioxo-4H-pyrano[3,2-d]pyrimidine-5,6-dicarboxylate and dimethyl (E)-2-((2,6-dimethylphenylamino)-(1,3-dimethyl-2,4,6-trioxo-pyrimidine-5-ylidene)-methyl)-but-2-enedioate in a nearly 1:1 ratio
and an overall yield of 85%. Dynamic effects were observed in the 1H NMR spectra of these compounds and were attributed to restricted rotation around the aryl-nitrogen single bonds and the
polarized carbon-carbon double bond.
Received September 18, 2000. Accepted (revised) November 22, 2000 相似文献
15.
Summary. Indole-2-carboxylic acid hydrazide was prepared and allowed to react with aromatic aldehydes in acidic medium to give the
corresponding hydrazone derivatives in good yields. The hydrazones were cyclized to indolo[2,3-d]pyridazine derivatives by refluxing with acetyl chloride. The indole carbohydrazide was converted to 2-triazolylindoles which
acted as starting materials for several indole derivatives. A number of new indole derivatives were also prepared and structurally
confirmed.
Received October 17, 2000. Accepted (revised) December 12, 2000 相似文献
16.
Barbara Zaleska Robert Socha Maria Ciechanowicz-Rutkowska Tulio Pilati 《Monatshefte für Chemie / Chemical Monthly》2000,131(11):1151-1160
Summary. An NMR study of the equilibriummixture of two conformers of 2-anilino-2-ethoxy-3-oxothiobutyric acid anilides 3 allows to estimate their population ratio in solvents of increasing polarity. X-Ray analysis as well as IR spectroscopy confirmed
that the conformer present in the solid state is stabilized by two hydrogen bonds. The structural basis of the second conformer
observed in solution is the 1,4-type S⋯O interaction between the sulfur of the thioanilide moiety and the oxygen of the ethoxy
group with a distance of 2.878 ?.
Received May 29, 2000. Accepted (revised) July 14, 2000 相似文献
17.
Avijit Banerji Kaustabh Kumar Maiti Sunanda Haldar Chaitali Mukhopadhyay Julie Banerji Thierry Prangé Alain Neuman 《Monatshefte für Chemie / Chemical Monthly》2000,131(8):901-911
Summary. Studies on cycloadditions of C,N-diarylnitrones to cinnamic acid amides were carried out. The diastereoisomeric (I, II) and (in some cases) regioisomeric (III) cycloadducts obtained were characterized by spectroscopic and X-ray data. Conformational studies were carried out by molecular
modelling.
Received February 8, 2000. Accepted February 18, 2000 相似文献
18.
Zorica M. Bugarčić Biljana Mojsilović Ljiljana Marjanović Stanimir Konstantinović 《Monatshefte für Chemie / Chemical Monthly》2000,131(10):1091-1096
Summary. The reaction of some alkenols with tetrachloromethane in the presence of a radical initiator was investigated. Regarding
the effects of structural features of the starting alkenol (number and position of methyl substituents at the double bond
and at the carbinol carbon atom, constitutional relationship between the double bond and the hydroxyl group) there are two
possible competing reactions: addition and cyclization. In the case of the simplest alkenols (without substituents and with
a more remote double bond) addition occurs; mono- and disubstituted secondary and tertiary Δ4- and Δ5-alkenols cyclize in high yields to give the corresponding cyclic ethers.
Received March 17, 2000. Accepted (revised) May 31, 2000 相似文献
19.
Saeed Balalaie Armin Arabanian Mehri S. Hashtroudi 《Monatshefte für Chemie / Chemical Monthly》2000,131(9):945-948
Summary. Zeolite HY and silica gel efficiently catalyzed the three component condensation of benzil, benzaldehyde derivatives, and
ammonium acetate under solvent-free conditions and microwave irradiation.
Received February 22, 2000. Accepted (revised) March 22, 2000 相似文献
20.
Ahmed A. Abdel Gaber Othman A. Farghaly Mahmoud A. Ghandour Hamdy S. El-Said 《Monatshefte für Chemie / Chemical Monthly》2000,131(10):1031-1038
Summary. The interaction of Ca(II), Cu(II), Zn(II), Pb(II), and La(III) ions with the antibiotics cephalexin, cefadroxil, cephaloridine,
and cefoperazone as secondary ligands was investigated potentiometrically. The formation constants were determined for a ligand-to-metal
ratio of 1:1 at 25°C and KNO3. The protonation constants of the complexes were evaluated for the system . The order of stability of the binary and ternary complexes were examined. It was found that glycine adds preferably [M(II)-cephalosporin] rather than to the aqueous complexes of M(II). In all cases 1:1:1 complexes were formed.
Received February 4, 2000. Accepted (revised) May 10, 2000 相似文献